Vibrator



D 25,1951 J. ca, M. BRODEN 2,579,784

N AIQR Filed April 11, 1946 3 Sheets-Sheet l Dec. 25, 1951 J. G. M. BRODEN 2,579,784

Smaentor John Gash-F Mauvii Braden (Ittorneg Dec. 25, 1951 J. G. M. BRODEN VIBRATOR 3 Sheets-Sheet 5 Filed April 11, 1946 Patented Dec. 25, 1951 VIBRATOR John Gustaf Mauritz Brodn, Malmo, Sweden,

assignor to Kockums Mekaniska Verkstads Aktiebolag, Malmo, Sweden, a corporation of Sweden Application April 11, 1946, Serial No. 661,216 In Sweden April 28, 1945 8 Claims.

One object of the invention is to provide a vibrator for converting with high emciency a direct-current in a pressure medium, such as air or gas, into a pulsating current, the said vibrator consisting of an oscillating member, suitably of the diaphragm type, which is arranged between a chamber onthe one side and one end of both an inlet and outlet passage for the pressure medium on the other side. The foremost condition which must be fulfilled for this purpose is that the oscillating member after each opening and passing of a quantity of pressure medium from the inlet passage to the outlet passage, shall close this connection again effectively.

Another object is to provide a. vibrator the oscillating member of which during the opening and closing of the said connection moves in resonance with the column of the pressure medium in the outlet passage.

A further object is to provide a self-controlled vibrator for signal apparatus which comprises a resonator or outlet passage which partly reflects and partly radiates the oscillation energy or transmits it in some other manner.

The invention is described herewith in the form of examples with reference to the accompanying drawings.

Fig. l of the drawing shows diagrammatically a longitudinal section through a vibrator according to the invention for a signal apparatus. Figs. la and 1b are diagrammatic views illustrating various parts and forces acting thereon during the assemblance of the vibrator. Fig. 1c is a sectional view to an enlarged scale of part of the vibrator. Fig. id is a sectional view taken on the line ldld, Fig. 1c. Figs. 2 and 3 show variants for the fixing of the oscillating member.

Although the invention is herewith described in its application to signal apparatus, this must not be understood as a limitation of the inventions scope since the latter can be used wherever it is desired to convert a direct current in a pressure medium into a pulsating current.

. The vibrator according to Fig. 1 comprises a casing I with a cover 2, both provided with a flange 3 and 4, respectively, said flanges being connected to each other by means of bolts 5. The inlet passage 6 and the outlet passage 1 are provided with screw threads 8 and 9 for the connection of an inlet tube for the compressed air and a horn or resonator H] which communicates with the passage 1. The inlet passage 6 opens into an annular chamber II in the casing l, the said chamber ll surrounding the inner end of the outlet passage 1 which is formed by a tube3'l extending into the casing and having an annular edge l9.

The oscillating member consists of two discs or diaphragms l2 and i3 of which the disc I2 is circular and substantially unperforated, whereas the disc [3 is circular and provided with a large central hole so that it has the form of a ring. The ring I3 has a somewhat larger external diameter than the disc 12.

The flanges 3 and 4 each have an outer, l4 and I5, and an inner, It and H, annular contact face or edge, of which the outer edges l4 and I5 are laid against one another when the flanges are tightened up, and the inner edges I6 and Ill clamp the ring 13 between them. Between the outer, l4, l5, and inner contact edges l6, H, a gap 18 is formed serving the purpose when the bolts 5 are drawn up, of causing the flange 4 to bend in towards the gap l8, thereby causing the ring l3 to be subjected to forces directed radially outwards around its entire circumference For this purpose the contact edges Ii, [5 should be so constructed that they come into contact with each other before the contact edges [6, ll clamp the ring l3 between them. This mode of action is more clearly illustrated in Fig. la which shows the flanges 3 and 4 at the moment the contact edges l4 and I5 come into contact with each other as a result of the action of the force F exerted by the bolts 5. Upon continued action of said force, the contact edge ll will be moved towards edge IS. The flange 4 may then be regarded as a lever having its fulcrum at point P, and the endof the lever or edge I! will move along a circular path as indicated by the arrow C. During this movement, the force f' (Fig. 1b) which clamps the ring i3 between the edges H and [6, will consequently be directed slightly towards the left, as viewed in Figs. la and 1b, and may be regarded as the resultant of a vertical force iv and a horizontal force in.

the last-named force being directed radially outwards and actsupon the ring i3 just when said ring is being clamped between the edges I6 and ll. The outlet passage 7 is constructed in such a manner that its contact edge 19 against the ring l3 lies in a plane which differs from another plane determined by the contact edge It. In Fig. l the first plane lies below the latter one. In consequence of this, when the ring 13 is clamped between the cover and the casing, the ring 13 will lie with'its inner peripheral portion pressed against the edge 19 of the outlet passage and will assume a certain curvature. Owing to the fact that the ring l3, on being clamped in the casing, is subjected to forces, exerted radially outwards around its circumference as mentioned above, these forces will not reduce but will rather increase the contact pressure of the ring |3 against the edge 19 of the outlet passage. If on the contrary these forceswere directed radially inwards, they would tend to bend the ring l3 downwards and accordingly to ease the contact pressure against the edge H! which in certain cases might cause the contact to cease entirely whereby the vibrator would be placed out of operation. The method of clamping the ring l3 in the casing is therefore of some importance with respect to the functioning of the vibrator.

The disc I2 is inserted with a slight radial clearance in a recess 22 in the cover 2. Thus, it has a certain movement in its own plane. The depth of the recess 20 is such that the disc i2 in its mounted position presses against the inner annular edge portion of the ring l3, and by means of the same pressure at its circumference, it lies against the bottom of the. circular recess 20. Between the discs l2 and I3 and the inner wall of the cover 2 an annular space 38 having a triangular cross-section will thus be formed. At the same time a closed chamber 2| will be formed between the cover 2 and the disc |2.

To facilitate the assembly of the cover 2 and discs l2 and I3 with the casing the discs l2 and I3 are placed in recesses in the cover and screws 22 are screwed into the cover 2 around the circumference of the ring 13, the said screws holding the ring l3 in position by means of their heads without clamping the ring tight. The disc i2 is thereby also held in position although it possesses a certain axial movement. By this means the cover with the discs can easily be set in its correct position with respect to the casing and screwed up tight by the bolts 5. In the casing recesses 23 are provided corresponding to the heads of the screws 22.

The chamber 2| may be entirely closed, but in order to prevent the occurrence of too high an internal pressure in the chamber which might render the starting of the vibrator diificult or even impossible in some cases, the chamber 2| may suitably beprovided with a very small hole 24 which connects the chamber with the surrounding atmosphere and thus gradually reduces the internal pressure inthe chamber. In Fig. 1 this hole 24 is arranged in an inner projection 25 which extends from the cover into the chamber and is provided on the outside with a bore 26 having a relatively large diameter. By means of this arrangement the entrance of dirt into the hole is prevented since the hole 24 is well protected. In place of the hole 24 a corresponding hole 21 may be formed in the disc |2 whichconmeets the interior of the chamber 2| with the outlet passage L In Fig. 1 the annular space 36 with the triangular cross-section between the discs l2 and I3 is in connection with the chamber 2| through the small gap between the circumference of the discs l2 and the wall of the cover and also through one or more recesses 28 in the contact face of the cover against the disc I2. In place of this connection the disc |2 may be provided with one or more holes 29 which directly connect the chamber with the annular space 36.

In Fig. 2 a variant of the method for fixing the discs I2 and I3 is shown. According to this method the contact edge of the casing against the ring I3 is replaced by a packing 3d. The figure shows further how an annular passage 3| is arranged around the circumference of the ring l3 and how this passage 3| is connected with the atmosphere by another passage 32. This arrangement has for its object to secure a satisfactory seal between the casing and the ring I3 and, in the event of compressed air leaking out between these parts notwithstanding, to lead this compressed air out to the atmosphere and prevent the compressed air from finding its way into the chamber 2| through the annular space.

Fig. 3 shows a third method of fixing the ring |3 according to which the ring extends the whole way between the two flanges 3 and 4 the contact surfaces of which are fiat. With this method of fixing the ring I3 is not-subjected to either inwardly or outwardly directed radial forces around its circumference and therefore has a contact pressure against the edge of the outlet passage which is not affected by the method of fixing the ring.

The outlet passage 7 has a special form which is described more particularly in connection with the Figures 4 and 5.

The mode of operation of the vibrator is as follows:

It may be assumed that the holes 21 and. 29 are,

which thereupon bends further downwards and opens a gap between the discs l2 and I3 so that the air also passes into the annular space 36 and flows on over the edge of. the disc l2 and through the recesses 28 into the chamber 2|. Owing to the increase of pressure in the chamber 2| and the internal stresses in the discs as well as the effect of the outlet passage 1, these forces will quickly overcome the air pressure on the upper side of the discs I2 and I3, which will move upwards and, lying in contact with one another, will close the connection between the inlet and outlet passages. A certain pressure has thus been set up in the chamber 2|, which pressure,

on the disappearance of the pressure wave from the inner portion of the outlet passage, willact as a tightening pressure against the disc I2. The air flowing out through the outlet passage will be set in oscillation owing to the form and length of the passage, and when a pressure is reflected at the open end of the outlet passage, an increase of pressure or a pressure surge will be produced at the inner end of the outlet passage, the said surge acting on the disc l2 which thereupon decreases its pressure against the disc 13. During this time the pressure in the chamber exerts a constant force on the disc l3 and,

when the pressure surge begins, the discs l2 and I3 will again be bent downwards and a fresh quantity of air will flow over from. the inlet passage to the outlet passage and a fresh quantity of air will pass into the chamber 2| if air has leaked out from the chamber 2| or if the air surge in question is more powerful than the preceding one, that is to say, if the strength of sound is increasing, whereupon the operation de: scribed will be repeated. The direct current of compressed air is thus converted into a pulsating current in the outlet passage. At the same time a part of the air flows out through the hole 24 from the chamber into the atmosphere. This loss is small however, on account of the small dimension of the hole 24 and as long as the vibrator is in operation the loss is replaced by fresh air which flows in between the discs i2, 13, round the disc 12 and through the recess 28. Without the hole 24, the chamber 2! would also be under pressure during the time in which the vibrator is not in use which might have the result that when it was desired to start the vibrator the pressure in the chamber 2| would be so great that the compressed air in the annular chamber ll would not suflice to press down the discs i2, l3, and open the connection with the outlet passage, so that the vibrator would not be able to start. Generally speaking however, notwithstanding good sealing arrangements, there is some leakage which gradually reduces the pressure in the chamber 2!. If therefore it is desired to start the vibrator immediately after it has been in use, this leakage may be insuihcient and in order to be on the safe side an artificial leak is advantageously introduced in the form oi the hole 24. replaced by the hole 2'! which provides for a restricted communication between the chamber 2| and the outlet passage 1. Similarly the connection through the recess 28 and over the gap between the disc I2 and the cover 2 may be re placed by the hole 29 in the disc l2.

From the foregoing it will be seen that it is important that the air from the chamber ll be not able to penetrate round the periphery of the disc l3 into the chamber 2!. In order to prevent the air from the chamber 1 I from penetrating between the discs 12 and 3 at the inner edge of the disc l3, when said discs are in the positions shown in the drawing, the inner peripheral portion of the disc 13 should slightly extend inside the contact edge l9.

What I claim is:

1. A vibrator comprising a casing, an inlet passage for the supply of fluid under pressure into said casing, a tube extending into said casing and it having an annular edge at its inner end, said tube forming an outlet passage for said fluid, a sound amplifying member communicating with said outlet passage, a vibratory diaphragm ring supported at its outer periphery in an air-tight manner by said casing and bearing at its inner periphery against said annular edge, a vibratory diaphragm disc supported at its periphery by said casing and bearing against the inner periphery of said ring, said disc and said ring and said casing forming between them an annular space, said ring being located between said inlet passage and said annular space, a substantially closed chamber on one side of said disc in opposite relation to said space and said outlet passage, and an open communication between said space and said chamber, said ring and said disc being operative by the differential between the pressures prevailing on both sides thereof to force said ring out of contact with said annular edge and said disc out of contact with said ring, whereby to permit flow of fluid from said inlet passage to said outlet passage and into said space and said chamber, and to seat said disc on said ring and to seat said ring on said edge, whereby to prevent flow of fluid from said inlet passage and from said space to said outlet passage.

2. A vibrator comprising a casing, an inlet passage for the supply of fluid under pressure into said casing, a tube extending into said casing and In such cases the hole 24 may be having an annular edge at its inner end, said tube forming an outlet passage for said fluid, a sound amplifying member communicating with said outlet passage, a vibratory diaphragm ring supported at its outer periphery in an air-tight manner by said casing and bearing at its inner periphery against said annular edge, a vibratory diaphragm disc supported at its periphery by said casing and bearing against the inner periphery of said ring, said disc and said ring and said casing forming between them an annular space being substantially triangular in cross-section, said ring being located between said inlet passage and said annular space, a, substantially closed chamber on one side of said disc in opposite relation to said space and said outlet passage, and an open communication between said space and said chamber, said ring and said disc being operative by the differential between the pressures prevailing on both edges thereof to force said ring out of contact with said annular edge and said disc out of contact with said ring, whereby to permit flow of fluid from said inlet passage to said outlet passage and into said space and said chamber, and to seat said disc on said ring and to seat said ring on said edge, whereby to prevent flow of fluid from said inlet passage and from said space to said outlet passage.

3. A vibrator comprising a casing, an inlet passage for the supply of fluid under pressure into said casing, a tube extending into said casing and having an annular edge at its inner end, said tube forming an outlet passage for said fluid, a sound amplifying member communicating with said outlet passage, said casing comprising two parts, each part having an external flange, bolts securing said flanges to each other, said flanges having interengaging contact faces located outside said bolts and contact faces located inside said bolts, a vibratory diaphragm ring supported at its outer periphery between said last-named contact faces and bearing at its inner periphery against said annular edge, the distance between said first-named contact faces in a position of the casing parts'with their flanges facing each other with untightened bolts being slightly smaller than the distance between said secondnamed contact faces less the thickness of said diphragm ring, a vibratory diaphragm. disc sup-, ported at its periphery by said casing and hearing against the inner periphery of said ring, said disc and said ring and said casing forming be tween them an annular space, said ring being lo cated between said inlet passage and said annular space, a substantially closed chamber on one side of said disc in opposite relation to said space and said outlet passage, and an open communication between said space and said chamben'said ring and said disc being operative by the differential between the pressures prevailing on both sides thereof to force said ring out of contact with said annular edge and said disc out of contact with said ring, whereby to permitflow of fluid from said inlet passage to said outlet passage and into said space and said chamber, and to seat said disc on said ring and to seat said ring on said edge, whereby to prevent flow of fluid from said inlet passage and from said space to said outlet passage.

4. A vibrator comprising a casing, an inlet passage for the supply of fluid under pressure into said casing, a tube extending into said casing and having an annular edge at its inner end, said tube forming an outlet passage for said 7. luid. soiind ampiifnn m mber qomm ica n w h said out et, pa sage, a vib a ry iarhra ni i s pport d; a s. oute p i h y: in

ai -t h manner y a d c n an b arin i in Per e y a ains ai a n l d e. said outer periphery being located. in a plane. different from a plane contacting said annular edge. a bra a a m d uppor e at s.

periphery by said casing and bearin v a ainst he nne pe i h y of a d in a sc an said ring and said casing iormi'ng between them an annular spaoe said ring being located between said inletpassage and said. annular space, a substantially closed chamber on one side; of; said discopposite. relation to said space and said utle passa e a d an, pen comm nica o b tweensaid space and said chamber, said ring and said disc beingoperative by the, difierential be-v tween thev pressures. prevailing in both sides thereof to force saidrii out of contact with; said annul r d n s id is ut f C n a t. th

said ring, whereby to permit flow of fluid fromv said, inlet; passage to said outlet passage and: into said-, space and said chamber, andto seatsaid discon said ring and to seat said ring on said, edge, whereby to prevent flow, of fluid from said inlet passage and from said space to; said: outlet, passage.-

5. A vibrator comprising a casing, an inlet passage; for; the supply of; fluid underpressure intosaid casing, atubegextending into said casing and having an annular edge at its inner end, said tube forming an outlet passage for said fiuid, a sound amplifying member communicating with said, outlet passage, a vibratory diaphragm; ring supported at. its outer periphery. in; an air-tight mannerby said casing; and bearing at its. inner periphery against said annular edge, a; vibratory diaphragm .discsupported, at its periphery. by said; casing andbearingagainst the inner periphery of R disc. out of contact with said ring, whereby to permit flow oif'fluid from said inlet passage to said outlet-passage and intosaid space and said, chamber, and to seat said disc onsaid ring andv te seat. said ring on said edge, whereby to preventf flow of fluid from said inlet passage, and.

from said spacelto, said outlet passage.

6,.A vibrator comprising a. casing, an inlet passage for the supply of fiuid under. pressure into said casing, a tube extendingv into said casing andhaving an annular edge at its inner end, said. tube, formingan outletpassage for said fluid,,a,

sound amplifying member communicating with said outletpassage, avibratory diaphragmring supported at its outer periphery in an air-tight, manner by'said casing. and bearing, at its inner periphery against said annular edg e,, a vibratory diaphragm disc supported at its periphery by said casing and bearing against the inner periphery of said ring, said disc and said ring and,

said casing forming between them an annular speec said ring being located between said, inlet passage and said annularspace, and a substantilly closed. chamber on one side of said disc in opposite relation to. said space and said outlet. passage, said, disc having an aperture'forming an open communication between said space. and said chamber, said ring and said disc being operative. by the differential between the pressures. prevailing on both sides. thereof to force said ring out. of contact with. said annular edge and said. discv out of contact with said. ring, whereby to permit; flow of. fluid from: said inlet passage to said outlet passage and into saidspace. and said chamber, andv to seatsaid disc on. said. ring and:

to seat. said ring on said edge, whereby to prevent flow of fluid from said inlet passage and from saidspace to said outlet passage.

7. A. vibrator comprising a casing, an inlet passage for the supply of fluid under pressure into said casing, a tube extending into said casing. and having an annular edge. at its inner end, said tube forming an outlet passage for. said fluid,

a soundamplifying member communicating with said outlet passage, a vibratory diaphragm ring supported atits outer periphery in an air-tight, manner by said casing and bearing at its inner periphery againstsaid annular edge, a vibratory diaphragm disc supported at its periphery by saidcasing and'bearing against the inner periphcry of said ring, said disc, and said ring and said casing forming between themv an annular space, said ring being located between said inlet passage and said annular space, a substantially closed chamber on one side of said disc in opposite relation to said space and said outlet passage, said; disc, having a restricted opening between said chamber and said outlet passage, and an open communication between said spaceiand said chambersaid ring and said disc being operative by the differential between the pressures prevail ing on both sides thereof to force said ring out of contact with said annular edge andsaid disc out of contact with said ring, whereby to permit flow of fluid, from said inlet passage to said outletpassageandintolsaid space and said chain-- ber, ,and to, seat said disc on said ring and to seat said ring on, said edge, whereby to prevent flow of. fluid, from, said inlet. passage and from said space tosaid,outlet-passage.

8.. Avibrator comprising a casing, an inlet pas.- sage, for the. supply of. fluid under pressure into. said casing, a, tube. extending into said casing andhayingan. annular edge at its inner end,.said' tube forming;anoutletpassage for said'fluid, a sQlmd; amplifying member communicating with said outlet passage, as vibratory diaphragm ring. supported at its outer, periphery in an air-tight manner by said. casing and bearing. at its inner periphery against saidannular edge, a vibratory diaphragm disc supported at its periphery by said casing, and bearing against the inner periphery of; said} ring; said disc and said ring and said casing iormingbetween them an annular space, said ring being located between said inlet passage and said annular space, a substantially closed chamber onone side of said disc in opposite-relation to said space andsaid outlet passage, said chamber having; a restricted communication with-theambient air, and an openycommunication' between said" spacef and said. chamber, said ring andsaidj disc being operative by the differential-between the pressures prevailing on bothsides thereof" to, force said ring out of contact with said-annular edge and said'discj out oficontact withusaidring, whereby to permit new of. fluid fromrsaid' inlet passage to saidjoutletpassage and into said space and said chamber, and

to seat said disc on said ring and to seat said ring on said edge, whereby to prevent flow of fluid from said inlet passage and from Said space to said outlet passage.

JOHN GUSTAF MAURITZ BRODEN.

REFERENCES CITED Number 10 UNITED STATES PATENTS Name Date Teste et a1. Oct. 15, 1918 Cooper Mar. 27, 1928 Harrison Oct. 8, 1929 Harrison May 6, 1930 Cahill June: 13, 1939 Lewis Feb. 24, 1942 

